1. Field
The present disclosure relates to techniques for designing semiconductor devices. More specifically, the present disclosure relates to a semiconductor device with a trench Schottky diode in which the top surface of the semiconductor layer in the cell region has a different height than the top surface of the semiconductor layer in the adjacent termination region.
2. Related Art
Schottky diodes are often used as rectifiers in power supplies. Trench Schottky diodes, in which parallel trenches in a cell or active region are used to provide isolation and to enhance depletion when the Schottky diodes are reversebiased, are often used to improve performance with respect to conventional Schottky diodes. In particular, trench Schottky diodes usually have improved forward voltage drop and reverse leakage current, which reduces forward losses and increases the maximum junction temperature. These improved characteristics reduce heat dissipation and enhance the safety margin of trench Schottky diodes.
Typically, trench Schottky diodes are fabricated using at least three photomasks in a photolithographic process. For example, a trench photomask, a contact photomask and a metal photomask may be used to define the structures in different layers in a trench Schottky diode. However, the use of multiple photomasks increases the cost of fabricating trench Schottky diodes and can reduce the yield.
Hence, what is needed is a semiconductor device, such as a trench Schottky diode, without the above-described problems.